Few months ago I bought the Section 8: prejudice from steam. And then I activated it using the account that I am using currently. After around one week of play I stopped playing this game. Today when I thought to play this game again then it asked for the product key of this game, and when I entered the key then the GFWL gives me an error saying the product key is invalid and therefore I am not able to play this game online again. I have the proof of purchasing this game and my product key is also valid then also it is showing that it is not a valid key. Is there anyone who can help me in this case? Please reply.